Aircraft turbine engine with epicyclic reduction gear having a variable reduction ratio

Abstract

An aircraft turbine engine includes a rotating body comprising a compressor rotor and a turbine rotor interconnected by a rotor shaft, the turbine engine being configured to drive a member by said rotor shaft via an epicyclic reduction gear, said epicyclic reduction gear comprising a first element (50) configured to be rotationally secured to said shaft, a second element (56) rotationally secured to said member, and a third element configured to be selectively secured to a stator of the turbine engine and disengaged from the stator, wherein the turbine engine comprises driving means to rotationally drive said third element at a piloted speed when it is disengaged from said stator.

1 . A turbine engine, comprising at least one rotating body comprising a compressor rotor and a turbine rotor interconnected by a rotor shaft, the turbine engine being configured to drive a member by said rotor shaft via an epicyclic reduction gear, said epicyclic reduction gear comprising at least one first element rotationally secured to said rotor shaft, at least one second element configured to be rotationally secured to said member, and at least one third element configured to be selectively secured to a stator of the turbine engine and disconnected from said stator, said turbine engine comprising a driving means configured to rotationally drive said third element at a piloted speed when it is disconnected from said stator, wherein said third element is connected to said stator a brake, and said driving means comprise a mechanical connection to said third element and a mechanical retrieval means for retrieving power from said turbine engine or from an external source, the driving means being configured so that the power retrieved by the mechanical retrieval means is transmitted by the mechanical connection to said third element to rotationally drive said third element. 
     
     
         2 . The turbine engine according to  claim 1 , wherein said third element is an outer ring gear of the epicyclic reduction gear. 
     
     
         3 . The turbine engine according to  claim 1 , wherein said driving means are reversible. 
     
     
         4 . The turbine engine according to  claim 1 , wherein said mechanical retrieval means are configured to retrieve power from at least one of said rotating body and said member. 
     
     
         5 . The turbine engine according to  claim 1 , wherein said mechanical retrieval means are connected to said epicyclic reduction gear. 
     
     
         6 . The turbine engine according to  claim 3 , wherein said mechanical connection are connected to said mechanical retrieval means by an electronic, electric or hydraulic circuit. 
     
     
         7 . (canceled) 
     
     
         8 . The turbine engine according to  claim 1 , wherein the turbine engine is one of: a turbine engine of a helicopter, said member being a helicopter rotor; a turboprop or turbine engine of an airplane, said member being a propeller or a fan; or an APU. 
     
     
         9 . A method for controlling a turbine engine according to  claim 1 , comprising:
 disengaging the rotor shaft and allowing the third element to rotate freely; and   operating the turbine engine while the third element is blocked by the brake.   
     
     
         10 . A method for controlling the turbine engine according to  claim 6 , comprising:
 starting the turbine engine with a motor-generator that forms the mechanical retrieval means and the driving means to rotationally drive the third element;   assisting the turbine engine with the motor-generator while the turbine engine rotates at a transient speed; and   providing APU power while the second element does not rotate, where the motor-generator is driven by the turbine engine.   
     
     
         11 . The method of  claim 10 , further comprising:
 braking the member while the motor-generator retrieves power from the member;   providing a power peak while the mechanical retrieval means provides power to said member from an external power source; and   turning off the turbine engine while the motor-generator provides power to said member from the external power source.